To determine the creased edges you could use the information of sharp edges on OBJ to create surfaces with sharp edges, or do it in two steps, ie import and choose edges that need to be sharpened, if you can implement this possibility I think it will be a thing much appreciated by many and as you can see the interest is increasing. I am available to provide some test object if necessary.

Hi pafurijaz,

> To determine the creased edges you could use the information of sharp edges on OBJ to create surfaces with sharp edges

I must admit that i have never seen an app supporting edges in .obj files, if i understand you correctly.

https://en.wikipedia.org/wiki/Wavefront_.obj_file

Regards
Stefan

<< Can anyone tell me why the pdf import did not work?

this PDF was an "image" file or a file "2D / 3D" ?

Hi eric,

re:
> I just tried to insert/import a pdf file into MoI 4 and had no luck. Nothing happened. (In Rhino it said there was no information)
> I convert the file from pdf to jpg and had no trouble bringing it into MoI as an image.
> Can anyone tell me why the pdf import did not work?

It's likely to be that the pdf file only contains bitmap image data in it and not vector drawing data.

When you open the pdf in Adobe viewer, if you zoom into areas does the display stay crisp like a vector drawing does, or do you see it getting blocky because it's made of pixels?

MoI and Rhino both only try to read vector drawing data out of a PDF file.

If there is no vector data in the file then converting it to a PNG or JPG image and bringing that in as a background image would be the way to go.

- Michael

Hi pafurijaz, yes if you could post an example .obj file that gives you sharp edges when smoothed in a polygon modeling program that would be helpful.

- Michael

Hi Chris,

> Okay, I didnt realize you were using obj as the format for importing polygons. Maybe
> selecting edges inside of moi and defining them as sharp before conversion could be a solution?

There is not currently any mechanism in MoI for working with polygon data in that way. That could be a possible solution in the future but I don't expect to have that for the MoI v4 timeframe, sorry.


> Right now in fusion I need to redo any edge weights after import as the fbx implementation in it doesnt seem to support edge weights.

Do you have any example fbx files that contain edge weight information? That could be a possibility in the future.

- Michael

Hi Michael,

just tested Wings3D .obj importer/exporter and surprisingly it contains hard edges information
in the .obj file. Unfortunately no other apps i tested understand those informations from Wings
3D.

I have also tested ZBrush's ZModeler which allows creasing and saved as various .fbx.
When reloading those .fbx files with creased edges into ZBrush the crease info is still
there but Silo don't understand the crease information, while loading the model fine.

So it seems with Wings 3D .obj it is only supported by Wings and .fbx crease informations
vary also between apps. I thought that at least .fbx would be compatible with creases
among various app. Maybe higher priced apps like Max, Maya etc. retain those infos with
ZBrush model exchange.

here' is also the .obj data and .mtl data from Wings3D:

# Exported from Wings 3D 2.1.5
mtllib testwings.mtl
o Scene.obj
#38 vertices, 32 faces
v -64.81151600 100.00000000 -37.81118400
v 64.81151600 100.00000000 -37.81118400
v -64.81151600 100.00000000 37.81118400
v 64.81151600 100.00000000 37.81118400
v 64.81151600 90.50128200 -37.81118400
v -64.81151600 91.21183800 -37.81118400
v 64.81151600 89.79074100 37.81118400
v -64.81151600 90.50128200 37.81118400
v 0.0000000e+0 121.31646700 -37.81118400
v 0.0000000e+0 121.31646700 37.81118400
v 0.0000000e+0 50.00000000 -37.81118400
v 0.0000000e+0 50.00000000 37.81118400
v 64.81151600 90.50128200 -37.81118400
v -64.81151600 91.21183800 -37.81118400
v 64.81151600 89.79074100 37.81118400
v -64.81151600 90.50128200 37.81118400
v 0.0000000e+0 50.00000000 -37.81118400
v 0.0000000e+0 50.00000000 37.81118400
v 79.07005300 94.87825800 -46.12964600
v -79.07005300 95.74514000 -46.12964600
v 79.07005300 94.01139800 46.12964600
v -79.07005300 94.87826500 46.12964600
v 0.0000000e+0 45.46669800 -46.12964600
v 0.0000000e+0 45.46669800 46.12964600
v 79.86074800 84.64553800 -46.59094200
v -79.86074800 85.52109500 -46.59094200
v 79.86074800 83.77001200 46.59094200
v -79.86074800 84.64555400 46.59094200
v 0.0000000e+0 34.73986800 -46.59094200
v 0.0000000e+0 34.73986800 46.59094200
v 89.04035200 101.26355000 -46.12241000
v 89.04035200 100.39668300 46.13688300
v 89.83104700 90.15530400 46.59817900
v 89.83104700 91.03083000 -46.58370600
v -89.04030600 101.26421400 46.13689000
v -89.83099400 91.03149400 46.59818300
v -89.04030600 102.13108100 -46.12240600
v -89.83099400 91.90703600 -46.58370200
vt 0.0000000e+0 0.0000000e+0
vt 4.9500000e-3 4.9500000e-3
vt 4.9500000e-3 0.99504900
vt 0.50000000 4.9500000e-3
vt 0.50000000 0.99504900
vt 0.99504900 4.9500000e-3
vt 0.99504900 0.99504900
vn 0.70710678 0.0000000e+0 -0.70710678
vn -0.70710678 0.0000000e+0 -0.70710678
vn 0.70710678 0.0000000e+0 0.70710678
vn -0.70710678 0.0000000e+0 0.70710678
vn 0.0000000e+0 0.0000000e+0 -1.00000000
vn 0.0000000e+0 0.0000000e+0 1.00000000
vn -0.39778100 0.89261383 -0.21215757
vn 0.40592154 0.88916570 -0.21121566
vn -0.39349896 0.89216266 0.22182054
vn 0.40167236 0.88875228 0.22085903
vn 3.6844692e-3 0.87806878 -0.47852027
vn 3.7144518e-3 0.87806871 0.47852015
vn -0.35580007 0.69330414 -0.62668627
vn 0.36006189 0.69160005 -0.62613481
vn -0.35226703 0.69004393 0.63225573
vn 0.35652884 0.68836134 0.63170076
vn 2.1179827e-3 0.49671650 -0.86791027
vn 2.1381601e-3 0.49770315 0.86734480
vn -2.6811362e-2 4.2950920e-2 -0.99871736
vn 2.7058927e-2 4.2967881e-2 -0.99870996
vn -2.7255302e-2 4.2879902e-2 0.99870840
vn 2.7503230e-2 4.2896666e-2 0.99870088
vn 2.3535063e-4 4.2964236e-2 -0.99907658
vn 2.3535257e-4 4.2964241e-2 0.99907658
vn 0.29798612 0.66521822 -0.68460864
vn 0.29473133 0.65993493 0.69110009
vn 0.69349349 8.5762380e-2 0.71534019
vn 0.69449421 8.5867973e-2 -0.71435599
vn -0.29467726 0.65997286 0.69108693
vn -0.69347861 8.5833549e-2 0.71534608
vn -0.29793206 0.66525660 -0.68459488
vn -0.69448002 8.5939444e-2 -0.71436119
vn -0.31243445 0.94993932 0.0000000e+0
vn -0.70710678 0.0000000e+0 -0.70710678
vn -0.70710678 0.0000000e+0 -0.70710678
vn 0.70710678 0.0000000e+0 -0.70710678
vn 0.70710678 0.0000000e+0 -0.70710678
vn 0.31243445 0.94993932 0.0000000e+0
vn -0.31243445 0.94993932 0.0000000e+0
vn -0.70710678 0.0000000e+0 0.70710678
vn -0.70710678 0.0000000e+0 0.70710678
vn 0.70710678 0.0000000e+0 0.70710678
vn 0.70710678 0.0000000e+0 0.70710678
vn 0.31243445 0.94993932 0.0000000e+0
vn 0.0000000e+0 0.0000000e+0 -1.00000000
vn -0.31243445 0.94993932 0.0000000e+0
vn 0.0000000e+0 0.0000000e+0 -1.00000000
vn 0.31243445 0.94993932 0.0000000e+0
vn -0.31243445 0.94993932 0.0000000e+0
vn 0.0000000e+0 0.0000000e+0 1.00000000
vn 0.31243445 0.94993932 0.0000000e+0
vn 0.0000000e+0 0.0000000e+0 1.00000000
g Scene.obj_default
usemtl default
s 1
f 3/2/39 10/4/49 9/5/46 1/3/33
s 2
f 2/7/38 9/5/48 10/4/51 4/6/44
s 3
f 1/3/34 6/3/2 8/2/4 3/2/40
f 1/3/35 9/5/47 11/5/5 6/3/2
f 4/6/42 7/6/3 5/7/1 2/7/37
f 4/6/43 10/4/50 12/4/6 7/6/3
f 5/7/1 11/5/5 9/5/45 2/7/36
f 5/1/1 13/1/7 17/1/11 11/1/5
f 6/1/2 14/1/8 16/1/10 8/1/4
f 7/1/3 15/1/9 13/1/7 5/1/1
f 8/2/4 12/4/6 10/4/52 3/2/41
f 8/1/4 16/1/10 18/1/12 12/1/6
f 11/1/5 17/1/11 14/1/8 6/1/2
f 12/1/6 18/1/12 15/1/9 7/1/3
f 13/1/7 19/1/13 23/1/17 17/1/11
f 14/1/8 20/1/14 22/1/16 16/1/10
f 15/1/9 21/1/15 19/1/13 13/1/7
f 16/1/10 22/1/16 24/1/18 18/1/12
f 17/1/11 23/1/17 20/1/14 14/1/8
f 18/1/12 24/1/18 21/1/15 15/1/9
f 19/1/13 25/1/19 29/1/23 23/1/17
f 19/1/13 31/1/25 34/1/28 25/1/19
f 20/1/14 37/1/31 35/1/29 22/1/16
f 21/1/15 32/1/26 31/1/25 19/1/13
f 22/1/16 28/1/22 30/1/24 24/1/18
f 22/1/16 35/1/29 36/1/30 28/1/22
f 23/1/17 29/1/23 26/1/20 20/1/14
f 24/1/18 30/1/24 27/1/21 21/1/15
f 26/1/20 38/1/32 37/1/31 20/1/14
f 27/1/21 33/1/27 32/1/26 21/1/15
f 32/1/26 33/1/27 34/1/28 31/1/25
f 35/1/29 37/1/31 38/1/32 36/1/30

and the .mtl file:

# Exported from Wings 3D 2.1.5
newmtl default
Ns 0.0
d 1.0
illum 2
Kd 1.0 1.0 1.0
Ka 1.0 1.0 1.0
Ks 0.0 0.0 0.0
Ke 0.0 0.0 0.0

Best regards
Stefan

Hi Stefan, thanks for testing that. So it looks like Wings3D is using the "s" statements for that?

Officially the s statements are used for setting "smoothing groups" but it's not referring to sub-d smoothing, it's for handling vertex normal generation where only polygons from the same smoothing group will be used for averaging vertex normals. That's for "smooth shading" control, not sub-d smoothing control.

The .obj file format predates the use of sub-d smoothing and so doesn't really have sub-d specific functions in it.

- Michael

Hi Michael,

well, i have no answer for this, but only see that it works with Wings3D...

Regards
Stefan

Hi Michael ...
That must be the problem ... the pdf image starts to fuzz out at about 800% zoom. The pdf file was created by a scan. Could it have been saved as a vector file at that time? How?
In any event converting it to a jpg file worked well enough.
thanks,
eric

Hi eric, usually a scan only generates bitmap image data and not things like line segment vector data.

There are some kinds of converter programs though that can convert it though. Another name for bitmap data is "raster data" and these kinds of converter programs are often referred to as Raster to Vector converters:
https://en.wikipedia.org/wiki/Comparison_of_raster-to-vector_conversion_software
https://en.wikipedia.org/wiki/Image_tracing

- Michael

Here is a sample fbx with some edge weighting. FBX version is 2018.

Is it how the wing3D model is supposed to look ?

That's a little trick I use sometimes to transfer edge weight with obj, by relying on vertex normal to define where the crease are supposed to be.
The idea is to split the vertex into points based on vertex normal attribute, create a group with the open edges, and on this edge selection I create the crease attribute the subdivision method is looking for, re-weld every points and apply the subdivision operation.

So yes it's a way to save crease in .obj, but I don't if this method is really reliable.

Hi PaQ,

yes, that is the model. However the creases (when using the "Hardness" command in Wings3D)
are 100 percent sharp. One can use also another option to soften them.


image hosting

Regards
Stefan

Hi, I explained myself badly, what I mean is better understood with a reference image that I enclose below and with some sample files.



As you can see the USB plug is exported with Moi3D in Obj and in the export Moi3D, mark the faces edges with sharp attribute, but as regards the conversion to SubD it is an unused attribute and could be used as an expedient case before finding a valid alternative.



And here some shading difference inside the awesome app CAD Assistant for phone that manage several type and conversion and many more features. Here the shading with edge sharp is better to understand the shapes.

https://www.opencascade.com/content/cad-assistant

And I attach the file in obj with marked sharp and no mark..

Hi pafurijaz, looking at the differences between your 2 .obj files it looks like the "sharp marked" one has different vertex normals. Vertex normals are meant to be used for shading polygons in display or rendering, not for subdivision smoothing control. Does Blender itself behave any differently between those .obj models if you import them back in and apply subd smoothing there?

- Michael

Yes, in fact it is as you said these are the normal info, used for smooth and sharp faces, No Blender only imports the attribute for shading that uses smooth and sharp shading. So could you use at this point the normal information being converted into Nurbs? Many 3D applications manage border information for normals.

Silouewette DFX export to modo.

AI export.

Hi pafurijaz,

re:
> So could you use at this point the normal information being converted into Nurbs?

No, not to get the same surface result that you would see by applying subdivision smoothing in a polygon modeling program.

That information is only used in programs currently for shading, not for controlling geometry shaping. Trying to use it for shaping would make the sub-d surface result in MoI look different than it does in all other programs which would be kind of weird. It's a goal to make the result in MoI behave the same as applying sub-d smoothing in other programs.

- Michael

Hi Chris,

just loaded your MODO .fbx into Silo and ZBrush. In Silo the creases come not through,
but in ZBrush it works!

Regards
Stefan